Robust transformation of singlet order into heteronuclear magnetisation over an extended coupling range

Single-scan measurements of nuclear spin singlet order decay rates

“…NMR methodologies that exploit various aspects of long-lived nuclear spin singlet order -all groupable under the name singlet NMR -are under constant development. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] The three main properties of this form of spin order -NMR silent, accessible on demand and long-lived -have found a variety of applications including: quantification, with enhanced sensitivity, of ligand binding; 18,19 measurements of very slow translational dynamics; [20][21][22][23][24][25] and their exploitation as molecular tags that can preserve information over a long time. [26][27][28][29][30][31][32][33][34][35][36] Long-lived spin order is exploited as a vehicle to preserve spin hyperpolarization gained through techniques such as PHIP, 37 SABRE 38 and dissolution-DNP.…”

Hyperpolarization read-out through rapidly rotating fields in the zero- and low-field regime

“…In particular, we have shown that the rotational direction plays an important role in correctly establishing the resonance condition, and should be chosen carefully in the experimental context. There are other methods to convert nuclear singlet order into heteronuclear polarization, including resonant pulse schemes in high field as well as magnetic field-cycling at low magnetic fields [10][11][12][13][14][15][16][17][18][19][20][21] . The STORM method introduced here is conceptually simple and provides a few advantages over other existing low field methods.…”

“…Particular promising techniques are para-hydrogen induced polarisation (PHIP) methods 1,2,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] . Methods of this type utilise molecular hydrogen gas enriched in its para-spin isomer, typically achieved by passing the cooled gas over an iron oxide catalyst 1,2 .…”

“…A number of techniques already exist for this purpose, both at high and low magnetic fields [10][11][12][13][14][15][16][17][18][19][20][21] . High field methods benefit from the usual advantages, spectral separation between heteroand homonuclei, strong pulse schemes with error compensation and applicability to a broad class of molecular systems 11,15,[21][22][23][24] . However, these benefits often come at a price.…”

Low-Frequency Excitation of Singlet-Triplet Transitions. Application to Nuclear Hyperpolarization

“…There are several other techniques for performing the transformation of nuclear singlet order to heteronuclear magnetization, including pulse techniques in high field [13,15,17,20,27], field-cycling and levelanticrossing phenomena [16,18,21,26], and low-field methods [18,21,25]. The WOLF method described here is highly intuitive, provides a very fast exchange of singlet and triplet populations, and has further potential advantages over current methods.…”